For example you can use the DATE function to create the dates January 1 1999 and June 1 2010 like this. There are some formulas can help you add or subtract weeks to date in Excel. DATE199911 Jan 1 1999 DATE201061 Jun 1 2010.
Date function in excel is a date and time function which represents the number provided to it as arguments in a date and time code the arguments it takes are integers.
The typical way to enter a date in Excel is to write the entire date within one cell but thats inconvenient when youre dealing with lots of information. It then adds 1 year from cell B2 resulting in 2020. When you specify the year month and day Excel produces a serial number that can then be formatted as a normal looking date. In other words number 43545 is 43545 days far from Jan 1 1990 which is the date Mar 21 2019.